The Melbourne mint opened its doors in 1872 but it wasn't until 1873 that the first half sovereigns were struck with an M mintmark underneath the shield. A total of 165,034 half sovereigns were struck in 1873 and unlike the early Sydney mint designs, the Melbourne mint had a standardised reverse design throughout the series though the obverse had three different variants.
The 1873 design features a slightly larger bust and a more detailed shield. The reverse of this date tends to appear a full grade better due to the hard-wearing nature of its intricate design with AU graded coins tending to have fully lustrous reverse. The date is relatively difficult to acquire with an estimated 1,500 to 2,000 pieces available. The date is available in mint state and one piece graded Choice Uncirculated was sold at the Reserve Bank Sale in 2005 which realised $36,000 plus commission (Downies, 2005) .